The primary goal of the Virus Production Core (VPC) (Core C) is to provide high quality purified virus stocks for the proposed experiments in each of the four projects, and for the preclinical testing studies performed by the Experimental Glioma Animal Model Core (Core B, EGAM Core-Gillespie), within this Program Project grant. The VPC will be responsible for the development of new methodologies necessary to achieve high quality, high titer virus stocks, free of contaminants. Establishment of such stocks is essential to ensure consistency and reproducibility between experiments and laboratories, both in vitro and in vivo, for all of the projects within the Program. A second goal of the VPC is to verify genotype of the viruses and characterize phenotype with respect to i) long-term titer stability, ii) replication competence, iii) oncolytic activity, and iv) foreign gene expression in selected tumor cell lines. Neurotoxicity and efficacy testing in vivo of each construct will be conducted within the EGAM Core- Gillespie. Finally, the VPC will establish and maintain a secure, Web-accessible database of each of the virus constructs developed for the different projects, as well as a database of all protocols relevant to the growth and characterization of these viruses, following a standard operating protocol template.